CN108139713B - Electronic clock - Google Patents

Abstract

The present invention provides an electronic timepiece, which is used for alleviating the difficulty of assembling operation in the electronic timepiece, and comprises the following components: a first drive wheel train (10) for driving the hour hand (4) at the time indicated on the dial by the hour hand (4), minute hand (5) and second hand (6); a second drive train (20) for driving the minute hand (5) and the second hand (6); a first detection unit (50) that detects a detection hole (12a) formed in the first drive train (10); and a detection portion (60) that detects the detection holes (22a, 23a, 24a) formed on the second drive train (20), and the detection hole (14a) of the hour wheel (14) of the first drive train (10) overlaps in the axial direction with the detection hole (22a) of the fourth wheel (22), the detection hole (23a) of the third wheel (23), and the detection hole (24a) of the fourth wheel (24) of the second drive train (20), and the detection hole (12a) in the first drive train (10) is formed on the second hour intermediate wheel (12) of a portion different from the portion of the detection holes (22a, 23a, 24a) in the second drive train (20) that overlaps in the axial direction.

Description

Electronic clock

Technical Field

The present invention relates to an electronic timepiece.

Background

In an electronic timepiece in which time is indicated by a plurality of indicating members such as hands, for example, there is a radio-controlled timepiece in which high-precision time information is acquired by receiving a signal, and the indicating members are forcibly driven based on the information, thereby indicating the high-precision time as the indicating members at any time.

Here, in order to drive the indicating member to the correct position, it is necessary to grasp the current position of the indicating member.

Therefore, a technique of detecting the current hand position using an optical sensor is known (for example, see patent document 1).

(Prior art document)

(patent document)

Patent document 1: japanese patent laid-open publication No. 013-

Disclosure of Invention

(problems to be solved by the invention)

In the electronic timepiece described in patent document 1, the first detection unit detects the hour intermediate wheel, and the hour wheel corresponding to the hour hand, and the second detection unit detects the fifth wheel, the fourth wheel, the third wheel, the second wheel, and the hour wheel corresponding to the second hand and the minute hand. Therefore, the hour wheel overlaps with the first detection section and the second detection section and is detected.

That is, 2 portions of the portion detected at the first detecting portion and the portion detected at the second detecting portion are formed on the hour wheel, and these 2 portions need to be formed in a specific positional relationship detected at the same timing.

Therefore, when assembling the wheel train corresponding to the hour hand and the wheel train corresponding to the second hand and the minute hand, the wheel train corresponding to the hour hand and the wheel train corresponding to the second hand and the minute hand need to be assembled while adjusting positions with high precision so that the wheel train corresponding to the hour hand and the wheel train corresponding to the second hand and the minute hand simultaneously form a specific positional relationship.

The above problem is common to all electronic clocks that detect the position of the pointing member, because the detection of the position of the pointing member can be performed not only in radio-controlled clocks but also in all electronic clocks.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an electronic timepiece capable of reducing difficulty in assembly work.

(means for solving the problems)

The present invention is an electronic timepiece, including: a display unit that displays time by at least a first indication member and a second indication member; a first drive train driving the first indicator member; a second drive train driving the second indicator member; the first drive train having a portion axially non-overlapping with the second drive train and a portion axially overlapping with the second drive train; the non-overlapping portions have a first specific portion; the overlapped portion has a second specific portion; a second detector that detects an overlap of the second specific portion and the third specific portion in the axial direction; a control section that controls driving of the first drive train and the second drive train based on a correspondence relationship, which is a reference of the first drive train and the second drive train, determined by a position of the first specific portion detected in advance by the first detector and a position of overlap in an axial direction of the second specific portion and the third specific portion detected in advance by the second detector.

(Effect of the invention)

According to the electronic timepiece of the present invention, the difficulty of the assembling work can be alleviated.

Drawings

Fig. 1 is a plan view showing a radio-controlled timepiece 1 as an embodiment of an electronic timepiece of the invention.

Fig. 2 is a perspective view showing a stepping motor, a drive train, a detection unit, and a control unit provided inside the radio-controlled timepiece 1.

Fig. 3A is a plan view of the stepping motor and the drive train of fig. 2, and is a view seen from the rear cover side of the radio-controlled timepiece 1.

Fig. 3B is a plan view of the stepping motor and the drive train of fig. 2, which is viewed from the dial side of the radio-controlled timepiece 1.

Fig. 4A shows the wheel of the fourth wheel in the train wheel (gear) in which the detection hole is formed.

Fig. 4B shows the wheel No. three of the train wheels (gears) in which the detection holes are formed.

Fig. 4C shows the second wheel in the train wheel (gear) in which the detection hole is formed.

Fig. 4D shows an hour wheel in a train wheel (gear) in which a detection hole is formed.

Fig. 4E shows a second time intermediate wheel in the train wheel (gear) in which the detection hole is formed.

Fig. 5 is a cross-sectional view showing a state in which the LED chip and the spot transistor are arranged at positions where the inspection hole of the hour wheel, the inspection hole of the fourth wheel, the inspection hole of the third wheel, and the inspection hole of the second wheel are axially overlapped.

Fig. 6 is a plan view showing a state in which the inspection holes of the hour wheel, the second wheel, the third wheel, and the fourth wheel are partially overlapped with each other in the axial direction.

Fig. 7 is a plan view corresponding to fig. 6, showing an example of when the phototransistor starts detecting light (detection start position) in the operation (c) and (iii).

Fig. 8 is a plan view corresponding to fig. 6, showing an example of the photo transistor before the photo transistor detects the light and ends (a position before the photo transistor detects the light).

Fig. 9 is a plan view corresponding to fig. 6 showing an example of the detection of the intermediate position.

Fig. 10 is a graph in which the detected light reception sensitivity P of each search position SK23 detected by the motions (c) (v) and (vi) is plotted on the horizontal axis with the search position SK23 of the houndstooth system and on the vertical axis with the light reception sensitivity P.

Detailed Description

(embodiment mode 1)

An embodiment of an electronic timepiece according to the present invention will be described below with reference to the drawings.

Constitution of radio wave correction timepiece

Fig. 1 is a plan view showing a radio-controlled timepiece 1 as an embodiment of an electronic timepiece of the invention, and fig. 2 is a perspective view showing a stepping motor, a drive train, detection units 50 and 60, and a control unit 70 provided inside the radio-controlled timepiece 1. Fig. 3A is a plan view of the stepping motor and the drive train wheel of fig. 2, which is viewed from the back cover side of the radio-controlled timepiece 1, and fig. 3B is a plan view of the stepping motor and the drive train wheel of fig. 2, which is viewed from the dial side of the radio-controlled timepiece 1.

As shown in fig. 1, the radio-controlled timepiece 1 of the present embodiment indicates the time of the mark 3 shown on the dial 2 by an hour hand 4 (an example of a first indicating member), a minute hand 5 (an example of a second indicating member), and a second hand 6 (an example of a second indicating member). The dial 2 and the hands (hour hand 4, minute hand 5, second hand 6) are examples of the display unit in the electronic timepiece of the invention.

The radio-controlled timepiece 1 further includes: an antenna that receives a signal (e.g., a standard radio wave) including time information; stepping motors 31, 41 and drive trains 10, 20 for driving the hands (hour hand 4, minute hand 5, second hand 6); and a control unit 70 configured by an IC or the like and configured to control the stepping motors 31 and 41 so as to accurately indicate the time based on the radio wave received by the antenna.

As shown in fig. 2, 3A, and 3B, the radio-controlled timepiece 1 includes a first stepping motor 31 for driving the hour hand 4 and a first drive train 10. Further, the first drive train wheel 10 drives a calendar plate as a pointer member indicating a calendar in addition to the hour hand 4, but the explanation about the calendar plate is omitted.

The radio-controlled timepiece 1 includes a second stepping motor 41 for driving the minute hand 5 and the second hand 6, and a second drive train 20. In the following description, the first stepping motor 31 and the first drive train 10 are referred to as an hour wheel system, and the second stepping motor 41 and the second drive train 20 are referred to as a minute-second wheel system.

The first drive train 10 includes a first hour intermediate wheel 11, a second hour intermediate wheel 12, a third hour intermediate wheel 13, and an hour wheel 14, and the second hour intermediate wheel 12 partially (partially) overlaps with a second drive train 20 described later, but a detection hole 12a described later formed in the second hour intermediate wheel 12 is a portion that does not overlap with the second drive train 20. The hour wheel 14 is a portion overlapping with the second drive train 20. The first drive train 10 transmits the driving force of the first stepping motor 31 in the order of the first hour intermediate wheel 11, the second hour intermediate wheel 12, the third hour intermediate wheel 13, and the hour wheel 14.

As shown in fig. 3A and 3B and fig. 4E described later, 1 detection hole 12a (an example of a first specific portion) is formed in the second intermediate wheel 12 so as to penetrate the gear in the axial direction. The second time intermediate wheel 12 is disposed at a position not overlapping with the hour wheel 14 in a plan view (a plane viewed in a direction orthogonal to the axial direction of the drive train wheels 10 and 20).

Fig. 4A shows the fourth wheel 22 of the wheel train (gear) formed with the detection hole 22a, fig. 4B shows the third wheel 23 of the wheel train (gear) formed with the detection hole 23a, fig. 4C shows the second wheel 24 of the wheel train (gear) formed with the detection hole 24A, fig. 4D shows the hour wheel 14 of the wheel train (gear) formed with the detection hole 14A, and fig. 4E shows the second hour intermediate wheel 12 of the wheel train (gear) formed with the detection hole 12 a.

The hour hand 4 is fixed to the hour wheel 14, and as shown in fig. 4D, 11 detection holes 14a (an example of a second specific portion) are formed to axially penetrate the gear. 11 detection holes 14a are formed side by side in the circumferential direction at angular intervals of 30[ degrees ] around the rotation center of the hour wheel 14. The angular interval between the 2 detection holes 14a, 14a at both ends of the 11 detection holes 14a is 60[ degrees ].

The control unit 70 controls the driving of the first stepping motor 31 so that the hour wheel 4 rotates 1 turn around the shaft for 12 hours at the time of normal needle operation. At this time, the second time intermediate wheel 12 rotates 1 turn around the shaft for 1 hour. The second hour intermediate wheel 12 rotates 1 revolution in response to the input of the step 60 to the first stepping motor 31, and the hour wheel 14 rotates 1 revolution in response to the input of the step 720 (60 × 12) to the first stepping motor 31. The reduction gear ratio of each gear train of the first drive gear train 10 is an example, and may be other reduction gear ratios.

The second drive train 20 includes a fifth wheel 21, a fourth wheel 22, a third wheel 23, and a second wheel 24, and transmits the driving force of the second stepping motor 41 in the order of the fifth wheel 21, the fourth wheel 22, the third wheel 23, and the second wheel 24. The second hand 6 is fixed to the fourth wheel 22, and as shown in fig. 4A, 1 detection hole 22a (an example of a third specific portion) is formed to penetrate the gear in the axial direction.

As shown in fig. 4B, 2 detection holes 23a (an example of a third specific portion) axially penetrating the gear are formed in the third wheel 23 at angular intervals of 180[ degrees ] between the centers of rotation. The minute hand 5 is fixed to the second wheel 24, and as shown in fig. 4C, 1 detection hole 24a (an example of a third specific portion) is formed to penetrate the gear in the axial direction.

Further, the 2 detection holes 23a of the third wheel 23 are holes longer than the other detection holes 22a, 24a in the circumferential direction.

Further, the control unit 70 controls the driving of the second stepping motor 41 such that the fourth wheel 22 rotates 1 turn around the shaft for 1 hour, the third wheel 23 rotates 1 turn around the shaft for 8 minutes, and the second wheel 24 rotates 1 turn around the shaft for 1 hour during normal needle operation (representing the operation of the time). At this time, the second time intermediate wheel 12 rotates 1 turn around the shaft for 1 hour.

The fourth wheel 22 rotates 1 rotation for the second stepping motor 41 in step 60, the third wheel 23 rotates 1 rotation for the second stepping motor 41 in step 480 (60 × 8), and the second wheel 24 rotates 1 rotation for the second stepping motor 41 in step 3600 (60 × 60). The reduction gear ratio of the third wheel 23 is an example, and may be other reduction gear ratios.

In the second drive train 20, the position in the rotational direction is adjusted so that the position in the plan view coincides with and overlaps in the axial direction 1 hour and 1 time at the time of normal needle transport, with the inspection hole 22a of the fourth wheel 22, the inspection hole 23a of the third wheel 23, and the inspection hole 24a of the second wheel 24.

Further, the 2 detection holes 23a of the third wheel 23 are long holes. This is because the second wheel 24 and the fourth wheel 22 are rotated coaxially, so that the inspection hole 24a and the inspection hole 22a are easily assembled in an overlapped state, and the third wheel 23, the second wheel 24 and the fourth wheel 22 are not coaxial, so that the inspection hole 23a and the inspection holes 22a and 24a are easily assembled in an overlapped state in a plan view. Therefore, the detection hole 23a may be the same circle as the other detection holes 22a, 24a as long as the combination of the detection holes 22a, 23a, 24a in the state of overlapping in the axial direction is not required.

The second wheel 24, the fourth wheel 22, and the hour wheel 14 have the same rotation center C, and constitute the rotation centers of the hour hand 4, the minute hand 5, and the second hand 6 as shown in fig. 1. That is, the first drive train 10 and the second drive train 20 are arranged such that a part thereof overlaps each other on the same axis.

The detection hole 14a of the hour wheel 14 is formed at a position axially overlapping with the detection hole 22a of the fourth wheel 22, the detection hole 23a of the third wheel 23, and the detection hole 24a of the second wheel 24 in an axially overlapping state.

However, the hour wheel 14 is driven by the first stepping motor 31, and the fourth wheel 22, the third wheel 23, and the second wheel 24 are driven by the second stepping motor 41. That is, the hour wheel 14 of the hour wheel system and the fourth wheel 22, the third wheel 23, and the second wheel 24 of the minute-second system can rotate independently of each other.

Therefore, even when the second drive train 20 is assembled by axially overlapping the detection hole 22a of the fourth wheel 22, the detection hole 23a of the third wheel 23, and the detection hole 24a of the second wheel 24, and the hour wheel 14 is assembled in a state where the detection hole 14a of the hour wheel 14 and the detection hole 22a, the detection hole 23a, and the detection hole 24a do not overlap each other, the detection hole 14a of the hour wheel 14 and the detection hole 22a, the detection hole 23a, and the detection hole 24a can be overlapped each other by driving the first stepping motor 31 and rotating the hour wheel 14.

Further, since the detection hole 14a of the hour wheel 14 is formed in 11, the hour hand 4 fixed to the hour wheel 14 is adjusted so that the detection holes 14a, 22a, 23a, and 24a are overlapped in the axial direction every 1 hour from the time of 0 indication (12 o 'clock) 00 min 00 sec and every 00 hour corresponding to the time of 10 indication (22 o' clock) 00 min 00 sec.

However, this is a structure for detecting the rotational position of the hour wheel 4 when the hour wheel 4 is rotated by 1 turn, and therefore, the detection holes 14a, 22a, 23a, and 24a are not limited to being adjusted so as to overlap in the axial direction every 1 hour from the time when the hour wheel 4 indicates 0 (12 o) 00 min 00 sec to the time when the hour wheel 4 indicates 10 (22 o) 00 min 00 sec.

Therefore, the detection holes 14a, 22a, 23a, and 24a may be adjusted so as to overlap in the axial direction at an interval of 1 hour from the time when the hour hand 4 indicates 1 hour (13 points) 00 minutes 00 seconds to the time when the hour hand indicates 11 hours (23 points) 00 minutes 00 seconds, or the detection holes 14a, 22a, 23a, and 24a may be adjusted so as to overlap in the axial direction at an interval of 1 hour from the time when the hour hand 4 indicates 23 (11 points) 00 minutes 00 seconds to the time when the hour hand 4 indicates 9 (21 points) 00 minutes 00 seconds.

The radio-controlled timepiece 1 further includes: second detection units 60 (an example of a second detector) that are disposed on both sides in the axial direction (axial direction) where the detection holes 14a, 22a, 23a, and 24a overlap at specific positions as described above, and that detect the overlap of the detection holes 14a, 22a, 23a, and 24a in the axial direction; the first detecting unit 50 (an example of a first detector) is disposed at both ends in the axial direction of the through-hole 12a at a specific position in the axial direction of the second intermediate wheel 12, and detects the through-hole 12 a.

The first detection unit 50 includes: an LED chip 51 that emits light; and a phototransistor 52 that detects light emitted from the LED chip 51. Since the gear of the second time intermediate wheel 12 is disposed between the LED chip 51 and the spot transistor 52, the light emitted from the LED chip 51 during most of 1 hour of 1 rotation of the second time intermediate wheel 12 is blocked by the gear of the second time intermediate wheel 12 and does not reach the phototransistor 52, and thus the phototransistor 52 does not detect the light.

However, only when the detection hole 12a of the second intermediate wheel 12 passes between the LED chip 51 and the photo transistor 52, the light emitted from the LED chip 51 reaches the photo transistor 52 and the photo transistor 52 detects the light. The result of the detection light by the phototransistor 52 is input to the control unit 70. That is, the control section 70 detects the rotational position of the first drive train 10 1 time every 1 hour.

Fig. 5 is a cross-sectional view showing a state in which the LED chip 61 and the spot transistor 62 are arranged at positions where the detection hole 14a of the hour wheel 14, the detection hole 22a of the fourth wheel 22, the detection hole 23a of the third wheel 23, and the detection hole 24a of the second wheel 24 axially overlap.

The second detection unit 60 includes, similarly to the first detection unit 50: an LED chip 61 that emits light; and a phototransistor 62 that detects light emitted from the LED chip 61. Since the hour wheel 14, the fourth wheel 22, the third wheel 23, and the second wheel 24 are disposed between the LED chip 61 and the spot transistor 62, the light emitted from the LED chip 61 during most of the rotation period of the hour wheel 14, the fourth wheel 22, the third wheel 23, and the second wheel 24 is blocked by any one of the hour wheel 14, the fourth wheel 22, the third wheel 23, and the second wheel 24 and does not reach the phototransistor 62, and the phototransistor 62 does not detect the light.

But instead. Only when the 4 detection holes 14a, 22a, 23a, 24a overlap in the axial direction, light from the LED chip 61 reaches the phototransistor 62 and the phototransistor 62 detects light (detects light). The result of detecting light by the phototransistor 62 is input to the control unit 70. That is, the control section 70 detects the rotational position of the second drive train 201 time every 1 hour. The control unit 70 also controls the amount of light emitted from the LED chip 61 and the light reception sensitivity of the spot transistor 62.

Although the timing at which the light spot transistor 52 detects light and the timing at which the light spot transistor 62 detects light do not necessarily coincide with each other, the time difference between the timing at which the light spot transistor 52 detects light and the timing at which the light spot transistor 62 detects light (the difference in the number of steps of driving the first stepping motor 31) always has a correspondence relationship with one fixed reference and does not change as long as each of the stepping motors 31 and 41 and each of the drive gear trains 10 and 20 operate normally. However, the time difference may be configured to be different for each individual difference of the radio-controlled timepiece 1.

The control unit 70 includes a storage unit 71 and a determination unit 72.

The storage unit 71 stores the number of steps of driving the first stepping motor 31 (hereinafter, referred to as the number of steps of reference; an example of a reference correspondence relationship between the detection hole 12a of the first drive gear train 10 and the detection holes 22a, 23a, and 24a of the second drive gear train 20) from the detection of light by the phototransistor 52 to the detection of light by the phototransistor 62 after the radio-controlled timepiece 1 is actually assembled. The storage section 71 stores the increase and decrease in the amount of light emitted from the LED chip 61 and the increase and decrease in the light reception sensitivity of the spot transistor 62, which are increased and decreased by the control section 70. Details will be described later.

The determination unit 72 determines whether or not the reference number of steps stored in the storage unit 71 matches the number of steps of driving the first stepping motor 31 from the detection of light by the phototransistor 52 to the detection of light by the phototransistor 62 in the use of the radio-controlled timepiece 1 described later (hereinafter, referred to as the actual number of steps; as an example of the actual correspondence relationship between the detection hole 12a of the first drive train system 10 and the detection holes 22a, 23a, and 24a of the second drive train system 20).

In addition, the case of inconsistency also includes the case where the phototransistor 62 does not detect light. Since the hour wheel 14 of the hour wheel system and the second, third, and fourth wheels 24, 23, and 22 of the minute wheel system rotate independently, the detection holes 14a, 22a, 23a, and 24a do not overlap in the axial direction even when the phase difference between the hour wheel system and the minute wheel system deviates from the reference step number, and therefore, in this case, the phototransistor 62 does not detect light and the timing (time) at that time indicates an incorrect (erroneous) state.

For example, if the reference number of steps from the detection of light by the phototransistor 52 to the detection of light by the phototransistor 62 in the initial stage (for example, at the time of completion of assembly) of the radio-controlled timepiece 1 is N1, the actual number of steps in use of the radio-controlled timepiece 1 thereafter also constitutes N1 during normal operation of the radio-controlled timepiece 1.

However, for example, when the radio-controlled timepiece 1 is subjected to an impact or the like and the rotor of the first stepping motor 31 is not rotated in accordance with the number of steps instructed by the control unit 70, the actual number of steps from the time when the phototransistor 52 detects light to the time when the phototransistor 62 detects light is deviated is, for example, N2 (a value different from N1), or the reference number of steps N1 is not matched because the phototransistor 62 cannot detect light because the relative positional relationship between the rotational position of the detection hole 14a of the hour wheel 14 and the rotational positions of the detection holes 22a, 23a, and 24a of the second drive train 20 is also deviated.

In this case, the time indicated by the radio-controlled timepiece 1 is a wrong time due to the positional deviation indicated by the hour hand 4, and the determination unit 72 determines that the time is a wrong time.

In addition, for example, when the radio-controlled timepiece 1 receives an impact or the like and the rotor of the second stepping motor 41 is not rotated in accordance with the number of steps instructed by the control unit 70, the positional relationship between the rotational positions of the detection hole 14a of the hour wheel 14 and the detection holes 22a, 23a, and 24a of the second drive train 20 is deviated, and the phototransistor 62 cannot detect light, so that the number of steps does not match the reference number of steps.

In this case, the positions of the minute hand 5 and the second hand 6 are shifted so that the time indicated by the radio-controlled timepiece 1 is an erroneous time, and the determination unit 72 determines that the time is an erroneous time.

When the determination unit 72 determines that the time indicates a wrong time, the control unit 70 controls the driving of the first stepping motor 31 and the second stepping motor 41 so that the actual number of steps from the detection of the detection hole 21a in the first drive train 10 by the phototransistor 52 to the detection of the detection holes 22a, 23a, and 24a in the second drive train 20 by the phototransistor 62 is set as the reference number of steps stored in the storage unit 71.

< operation of radio-controlled timepiece >

In the radio-controlled timepiece 1 configured as described above, when the second drive train 20 is assembled, the second detector 60 detects the detection holes 22a, 23a, and 24a, and positions the detection holes 22a, 23a, and 24a of the fourth wheel 22, the third wheel 23, and the second wheel 24 so as to overlap each other in the axial direction.

In the assembly, only the rotational positions of the 3 gear trains (the fourth wheel 22, the third wheel 23, and the second wheel 24) need to be aligned at the position detected by the second detecting portion 60.

Next, when the hour wheel 14 of the first drive train 10 is assembled coaxially with the second wheel 24 and the fourth wheel 22, it is not necessary to overlap the inspection hole 14a of the hour wheel 14 with the 3 inspection holes 22a, 23a, and 24a of the second drive train 20. In addition, the relationship (phase relationship) of the rotational positions between the detection hole 14a of the hour wheel 14 and the detection hole 12a of the second hour intermediate wheel 12 need not have a specific positional relationship.

That is, the gear train (gear) to be detected by the first detecting unit 50 is the second hour intermediate wheel 12, the gear train (gear) to be detected by the second detecting unit 60 is the hour wheel 14, the second wheel 24, the third wheel 23, and the fourth wheel 22, and the gear to be detected by the first detecting unit 50 is different from the gear to be detected by the second detecting unit 60.

Therefore, the radio-controlled timepiece 1 can reduce the difficulty of assembly as compared with a configuration in which the rotational positions of 4 or more gears (horn gears) are aligned in a specific state when the first drive train 10 and the second drive train 20 are assembled.

In addition, since the number of gear trains overlapping in the axial direction for detecting the rotational position is reduced, the thickness of the radio-controlled timepiece 1 can be reduced.

In the radio-controlled timepiece 1 in the assembled state, the control unit 70 first drives the first stepping motor 31 step by step (1 step), and the first detection unit 50 waits for detection of the detection hole 12a of the second time intermediate wheel 12 during the step of driving for 1 hour (the first stepping motor 31 and the second stepping motor 41 operate faster than normal hand movement (time indicated). When the first detection unit 50 detects the detection hole 12a, the detection result is input from the first detection unit 50 to the control unit 70.

The control unit 70 controls the detection of the rotational position of the first drive gear train 10 of the first stepping motor 31, the level (level) of light emitted from the LED chip 51, and the level of light received by the phototransistor 52 so as to be finely adjusted until the amount of light detected by the phototransistor 52 is maximized when the first detection unit 50 detects light.

The control section 70 stops the first stepping motor 31 when the detection result is input, and stores the detected level and the stopped rotational position of the first drive train 10 as the reference position in the storage section 71.

Next, the control unit 70 waits for the second detection unit 60 to detect light after driving the second stepping motor 41 for 1 hour while the first stepping motor 31 is kept stopped. Since the detection hole 22a of the fourth wheel 22, the detection hole 23a of the third wheel 23, and the detection hole 24a of the second wheel 24 of the second drive train 20 are adjusted in advance so as to overlap at the rotational position at which the second detector 60 can detect light, the rotational positions must overlap at a rate of 1 time per 1 hour.

However, since the second detection unit 60 is not aligned with the rotational position of the detection hole 14a of the coaxial hour wheel 14, the second stepping motor 41 may not detect light even if it is driven for 1 hour. In this case, after the step in which the second stepping motor 41 is driven for 1 hour, the first stepping motor 31 is driven for only 30 minutes and then stopped. That is, the rotational position of the detection hole 14a of the hour wheel 14 is moved by an angle of 15[ degrees ] only.

Thereafter, the second stepping motor 41 is driven stepwise for 1 hour while the first stepping motor 31 is kept stopped again, and then waits for the second detection unit 60 to detect light.

In this state, when the second detection unit 60 cannot detect light, the control unit 70 may control the rotation position of the detection hole 14a of the hour wheel 14 to be finely adjusted by, for example, stopping the first stepping motor 31 after driving for a further number of steps of only 15 minutes, and then operating the second stepping motor 41 to drive for 1 hour.

Further, in the present embodiment, the detection hole 14a formed on the hour wheel 14 is formed at an angle of every 30[ deg ] around the rotation center C, but since the size of the detection hole 14a itself is 15[ deg ] or more around the rotation center C, the size of the light-shielded portion between the adjacent two detection holes 14a is smaller than the angle of 15[ deg ] around the rotation center C. Therefore, in the present embodiment, if the rotational position of the detection hole 14a of the hour wheel 14 is moved by only 30 minutes (15[ degree ] angle), the second detection unit 60 is not able to detect light because the detection hole 14a is disposed in the light-shielded portion before rotation.

However, when the amount of emitted light of the LED chip 61 is reduced or the light receiving sensitivity of the phototransistor 62 is lowered, the second detection unit 60 may not detect light. In this case, the light quantity emitted by the LED chip 61 is increased or the light receiving sensitivity of the phototransistor 62 is increased so that the second detection unit 60 can appropriately detect light.

When the second detection unit 60 detects light, the control unit 70 repeats: detection of the rotational position of the first drive train 10 driven by the first stepper motor 31; detection of the rotational position of the second drive train 20 driven by the second stepping motor 41; the second stepping motor 41, the LED chip 61, and the phototransistor 62 are controlled by fine adjustment of the detection level of the light emission level (decrease in light amount) of the LED chip 51 and the light reception level (increase in light reception sensitivity) of the phototransistor 52.

When the first detector 50 detects the detection hole 12a of the second intermediate wheel 12, the controller 70 repeats the following operations: detection of the rotational position of the first drive train 10; the second stepping motor 41, the LED chip 51, and the phototransistor 52 may be controlled by fine adjustment of the detection level of the light emission level (decrease in the amount of light) of the LED chip 51 and the light reception level (increase in the light reception sensitivity) of the phototransistor 52.

The control section 70 stops the second stepping motor 41 after the fine adjustment, and stores the detected level and the stopped rotational position of the second drive train 20 as a reference position in the storage section 71.

The storage unit 71 stores the number of steps of driving the first stepping motor 31 from the reference position stored by the first detection unit 50 by detecting the detection hole 12a to the reference position stored by the second detection unit 60 by detecting the light.

The number of steps corresponds to a time difference between the first drive train wheel and the second drive train wheel between a reference position at which the first detecting unit 50 detects the detection hole 12a and stores the reference position and a time period at which the second detecting unit 60 detects the detection holes 22a, 23a, and 24a of the second drive train wheel 20 and the detection hole 14a of the hour wheel 14.

Therefore, the time difference stored in the storage unit 71 is a specific value of the radio-controlled timepiece 1.

The hour hand 4, minute hand 5, and second hand 6 are fixed to the hour wheel 14, second wheel 24, and fourth wheel 22, respectively, in a state where the second detection unit 60 detects that the detection holes 22a, 23a, 24a, and 14a overlap each other. In this case, the time indicated by the hour hand 4, minute hand 5, and second hand 6 is preferably a positive time such as 0 hour 00 minute 00 second. Accordingly, the relationship between the position indicated by each pointer and the detection holes 14a, 22a, 23a, and 24a is stored in the storage unit 71 in association with each other, or controlled by the control unit 70, which is set in advance as a correspondence relationship.

The hour hand 4 is fixed to the hour wheel 14, but the position indicated by the hour hand 4 may be associated with a position detected by the detection hole 14a at a time interval of 1 hour and 2 hours.

The control for detecting the reference position of the hour wheel system, that is, the reference position of the minute wheel system, is described in detail in < control for detecting the reference position > described later.

As described above, when the radio-controlled timepiece 1 in which the reference time difference is stored in the storage unit 71 is used as an assembled product, the control unit 70 counts the actual number of steps of the command to the first stepping motor 31 from the detection of the detection hole 12a by the first detection unit 50 to the detection of the detection holes 22a, 23a, 24a, and 14a by the second detection unit 60.

Then, the determination unit 72 compares the actual number of steps counted with the reference number of steps stored in the storage unit 71. As a result of the comparison, when the actual number of steps counted matches the reference number of steps, the determination unit 72 determines that the time indicated by the radio-controlled timepiece 1 is correctly indicated. On the other hand, as a result of the comparison, when the actual number of steps counted does not match the reference number of steps and when the second detection unit 60 cannot detect light, the determination unit 72 determines that the indication of the time indicated by the radio-controlled timepiece 1 is incorrect.

As described above, according to the radio-controlled timepiece 1 of the present embodiment, the actual number of steps counted from the time when the first detecting portion 50 detects the detecting hole 12a in the first drive train 10 until the time when the second detecting portion 60 detects the overlap of the detecting hole 14a of the hour wheel 14 and the detecting holes 22a, 23a, and 24a in the second drive train 20 in the axial direction can be compared with the reference number of steps stored in advance, and it is possible to easily determine whether the time indicated by the radio-controlled timepiece 1 is correct.

According to the radio-controlled timepiece 1, the correct and incorrect time can be determined at intervals of 1 hour, but the electronic timepiece of the present invention is not limited to this form, and may be configured to perform the determination at short time intervals or at longer time intervals.

In this case, the number of the detection holes 12a, 14a, 22a, 23a, 24a formed in the first drive train 10 and the second drive train 20 may be increased or decreased, or the detection holes may be formed in another train (gear) in the first drive train 10 or another train (gear) interlocked with the first drive train 10, or in another train (gear) in the second drive train 20 or another train (gear) interlocked with the second drive train 20.

In the radio-controlled timepiece 1, the detection hole 14a of the hour wheel 14 can detect only 11 times during 1 rotation, and therefore, the time cannot be determined as correct or incorrect 1 time in 12 hours, but the rotation position of the hour wheel 14 during 1 rotation can be determined because the time cannot be detected 1 time. That is, when the time interval of the light detection by the phototransistor 62 in 12 hours is not 1 hour but 2 hours, the "hour" of the time indicated by the hour hand 4 can be determined by the portion where the detection hole 14a is not formed before 1 hour.

The determination unit 72 drives the first stepping motor 31 and the second stepping motor 41 by the mode control unit 70, which constitutes the reference number of steps stored in the storage unit 71, in the case where the determination timing indicates that there is a mistake, by the actual correspondence relationship (time difference; number of steps) between the position of the detection hole 12a in the first drive train 10 detected by the first detection unit 50 and the position where the detection hole 14a of the hour wheel 14 and the detection holes 22a, 23a, and 24a in the second drive train 20 overlap in the axial direction detected by the second detection unit 60.

The control of the first stepping motor 31 and the second stepping motor 41 by the control unit 70 can be performed in the same process as the operation of storing the reference number of steps in the storage unit 71 after the assembly of the radio-controlled timepiece 1.

That is, the control unit 70 drives the first stepping motor 31 step by step, and waits for the first detection unit 50 to detect the detection hole 12a of the second timing intermediate wheel 12 during the step of driving for 1 hour (the first stepping motor 31 and the second stepping motor 41 are operated at a speed faster than that when the normal timing is shown).

When the first detection unit 50 detects the detection hole 12a, the control unit 70 drives and stops the first stepping motor 31 only by the number of steps stored in the storage unit 71. At this time, any one of the 11 detection holes 14a formed in the hour wheel 14 is arranged at a position (position detected by the second detection unit 60) overlapping with the 3 detection holes 22a, 23a, and 24a of the second drive train 20.

However, since there are 11 detection holes 14a of the hour wheel 14, there is a case where the middle portion of the portion where the angular interval between the adjacent 2 detection holes 14a is 60 degrees is arranged at a position overlapping with the 3 detection holes 22a, 23a, and 24 a.

Next, the second stepping motor 41 is driven for the number of steps of 1 hour, and waits for the second detection unit 60 to detect light. Even if the second stepping motor 41 is driven for only the number of steps of 1 hour and the second detection unit 60 cannot detect light, the portion where the detection hole 14a of the hour wheel 14 is not formed is arranged at a position overlapping the 3 detection holes 22a, 23a, and 24a as described above.

Therefore, the control unit 70 drives the first stepping motor 31 so as to rotate the second time intermediate wheel 12 by 1 rotation, and stops the first stepping motor 31 in a state where any one of the detection holes 14a of the time wheel 14 is arranged at a position overlapping with the 3 detection holes 22a, 23a, and 24 a.

Thereafter, the control unit 70 drives the second stepping motor 41 again for a maximum number of steps of 1 hour, and waits for the second detection unit 60 to detect light. When the second detection portion 60 detects light, the control portion 70 stops the driving of the second stepping motor 41.

In this state, the minute hand 5 and the second hand 6 are arranged at the initial reference positions. On the other hand, the hour hand 4 is also disposed at a position indicating any one positive time, but it is not known to indicate that "hour". Therefore, the control section 70 drives the first stepping motor 31 by the number of steps of rotating the hour wheel 14 by 1 turn (the number of steps of 12 hours), specifies the rotational position where the detection hole 14a is not formed at the same angular interval, and detects "hour" indicated by the hour hand 4.

Through the above operation, the control section 70 can determine the rotational position of each hand of the radio-controlled timepiece 1, and drive the first stepping motor 31 and the second stepping motor 41 so that each hand of the radio-controlled timepiece 1 is corrected by the time acquired by the radio wave based on the radio wave including the information on the time received by the antenna.

As described above, according to the radio-controlled timepiece 1 of the present embodiment, it is possible to detect and eliminate a deviation in the time indication due to the wear of the drive gear trains 10 and 20 of the stepping motors 31 and 41 caused by an input such as an impact in a short time of 1 hour.

In the radio-controlled timepiece 1 according to the present embodiment, the first detector 50 is disposed at a position not overlapping with the train wheels (the hour wheel 14, the fourth wheel 22, the third wheel 23, and the second wheel 24) to be detected by the second detector 60 in the plan view. Accordingly, the thickness of the radio-controlled timepiece 1 can be reduced compared to a configuration in which the first detection unit 50 is disposed at a position overlapping the train wheel to be detected by the second detection unit 60 in the plan view direction.

Further, the restriction of the arrangement position of the first detection portion 50 is reduced, and the first drive train 10 and the second drive train 20 can be arranged dispersedly. Accordingly, the thickness of the radio-controlled timepiece 1 can be further reduced, and the degree of freedom of the internal layout can be improved.

< modification of the construction >

The specific part of the electronic timepiece of the invention is not limited to the detection holes 12a, 14a, 22a, 23a, and 24a in the radio-controlled timepiece 1, and a notch or the like formed for detection may be applied.

Although the detection hole 12a of the first drive train 10 is formed in the second hour intermediate wheel 12, it may be formed in the first hour intermediate wheel 11, the third hour intermediate wheel 13, or another gear that is separately set so as to rotate in conjunction with these 3 hour intermediate wheels 11, 12, 13.

Although the phototransistor 52 of the detection portion 50 can detect light emitted from the LED51 and passing through the edge (edge) of the detection hole 12a, in terms of improving the detection accuracy of the rotational position, it is preferable to perform detection of light when the phototransistor 52 detects light passing through the geometric center of the detection hole 12 a. Then, when light passing through the center of the detection hole 12a is detected, the amount of light detected is larger than when light passing through the edge of the detection hole 12a is detected.

Therefore, the control unit 70 can improve the accuracy of detecting the rotational position of the first drive train wheel 10 by comparing the light amount detected by the phototransistor 52 with the light amount detected at the rotational position corresponding to the previous step for each rotational position of the second hour intermediate wheel 12 (step of driving the first stepping motor 31) and detecting the light by the detection unit 50 at the rotational position where the detected light amount is the largest.

Such control of detection can be similarly applied to the second detection unit 60.

In the radio-controlled timepiece 1 of the present invention, the LED chips 51 and 61 and the phototransistors 52 and 62 are combined, but other photodetectors and other detectors than light may be used.

Although the reference correspondence relationship in the electronic timepiece according to the present invention is the number of steps (reference number of steps) for driving the first stepping motor 31 in the radio-controlled timepiece 1 according to the present embodiment, the reference correspondence relationship may be the number of steps for driving the second stepping motor 41, or other physical quantities such as a time difference associated with the number of steps.

Although the above embodiment is a radio-controlled timepiece 1, the electronic timepiece according to the present invention is not limited to a radio-controlled timepiece. That is, the electronic timepiece according to the present invention is applicable to all electronic timepieces that detect the position of an indicating member such as a pointer, and is also applicable to an electronic timepiece that corrects a pointer indication based on a GPS signal, for example.

< control of detection of reference position >

The more detailed control contents of the control section 70 for detecting the reference position of the first drive train 10 in the hour wheel system and the reference position of the second drive train 20 in the minute wheel system will be described below.

In the operation of detecting the reference position, the control unit 70 drives the first drive train 10 and the second drive train 20 faster than in the normal needle-manipulating. The controller 70 counts the number of steps driven from the initial position S10 (not the initial position, but a specific position) of the first stepping motor 31 and the number of steps driven from the initial position S20 (not the initial position, but a specific position) of the second stepping motor 41, and stores the counted numbers in the storage 71.

(1) First, detection of the reference position SK1 of the first drive train 10 in the wheel system is carried out.

Specifically, as described above, the second time intermediate wheel 12 is rotated 1 time. The control unit 70 drives the first stepping motor 31 of the hour wheel system 60 steps from the initial position S10 in order to rotate the second hour intermediate wheel 12 1 time. During the second time intermediate wheel 12 rotates 1 revolution by the driving of the first stepping motor 31, the detection hole 12a passes over the line connecting the LED chip 51 and the phototransistor 52, and the passing of the detection hole 12a is detected by the phototransistor 52 at this time.

Here, it is conceivable that the detection is continued even in a plurality of steps of the rotation range including the rotation position of the detection hole 12 a. That is, even if the detection hole 12a is at a position deviated from the lines connecting the LED chip 51 and the phototransistor 52 by a plurality of steps, the light emitted from the LED chip 51 passes through the detection hole 12a, is continuously detected by the phototransistor 52, and is continuously detected by the first detection portion 50 at a plurality of positions where the first drive train 10 is driven.

However, if the detection state covering such a plurality of steps continues, the reference position SK1 of the time wheel system cannot be accurately determined. In the present embodiment, the intermediate position among the plurality of steps detected by the phototransistor 52 is set as the reference position SK1 of the hour wheel system.

Specifically, the second time intermediate wheel 12 is rotated, and when the phototransistor 52 searches for the light detection, the rotation position of the second time intermediate wheel 12 at which the light can be detected first is set as the detection start position Ss. Further, the detection start position Ss is the number of steps driven from the initial position S10 of the first stepping motor 31. After the light is first detectable, the rotation of the second time intermediate wheel 12 is continued, and the rotational position before the light is not detectable (the rotational position corresponding to the number of steps one step before the number of steps corresponding to the rotational position where the light is not detectable) is set as the position Se before the end of the detection. The position Se before the end of detection is the number of steps Se from the initial position S10.

When the amount of light emitted from the LED chip 51 and the detection sensitivity of the phototransistor 52 are appropriately set, normally, the detection start position Ss and the position Se before the end of detection do not coincide with each other and light is detected between a plurality of steps of the detection start position Ss and the position Se before the end of detection. Therefore, the reference position of the hour wheel system cannot be determined as 1 position.

In this case, the control unit 70 performs control such that the first stepping motor 31 rotates in the reverse direction to return the second intermediate wheel 12 to the position before the detection start position Ss, performs control such that the amount of light emitted from the LED chip 51 is reduced and the detection sensitivity of the phototransistor 52 is increased, and detects the detection start position Ss and the position Se before the detection is completed again.

At this time, although the detection sensitivity of the phototransistor 52 is improved more than that at the first time, since the emission light amount of the LED chip 51 is reduced, the width (the number of steps) between the detection start position Ss and the position Se before the end of detection is narrower than the width (the number of steps) between the detection start position Ss and the position Se before the end of detection at the first time.

Next, the control unit 70 controls the first stepping motor 31 to rotate in the opposite direction so as to return the second intermediate wheel 12 to the position before the detection start position Ss, and controls the LED chip 51 to reduce the amount of light emitted therefrom and the phototransistor 52 to increase the detection sensitivity, thereby detecting the detection start position Ss and the position Se before the detection is completed in the same manner as the previous time.

Similarly, the detection sensitivity of the phototransistor 52 is gradually increased while gradually decreasing the amount of light emitted from the LED chip 51, and the detection operation of the detection start position Ss and the position Se before the end of detection is repeatedly performed. The amount of light passing through the detection hole 12a is small when the light emitted from the LED chip 51 passes through the edge of the detection hole 12a and reaches the phototransistor 52, compared to the maximum amount of light passing through the detection hole 12a when the light emitted from the LED chip 51 passes through the center of the detection hole 12a and reaches the phototransistor 52.

Therefore, when the detection sensitivity of the phototransistor 52 is gradually increased while gradually decreasing the amount of light emitted from the LED chip 51, since light passing through the vicinity of the center of the detection hole 12a is detected, but light passing through the edge of the detection hole 12a is not detected gradually, the detection start position Ss and the position Se before the end of detection are close to each other and eventually light passing through the vicinity of the center of the detection hole 12a is not detected, and a state is constituted in which the detection start position Ss and the position Se before the end of detection are coincident with each other or close to each other.

When the detection start position Ss does not coincide with the position Se before the end of detection, the control unit 70 stores the coincident detection start position Ss (position Se before the end of detection) in the storage unit 71 as the reference position SK1 (i.e., S11) of the hour wheel system.

On the other hand, although the detection start position Ss does not coincide with the position Se before the end of detection, when the detection process is ended in a state of final approach (when the amount of light emitted from the LED chip 51 is reduced to the minimum level within the preset range), the control section 70 stores the detection start position Ss of the approach detection start position Ss and the position Se before the end of detection as the reference position SK1 (S11) of the hour wheel system in the storage section 71.

The control unit 70 rotates the first stepping motor 31 in reverse and stops the hour wheel system at the reference position SK 1. That is, the second time intermediate wheel 12 is stopped at a rotational position where the line connecting the LED chip 51 and the phototransistor 52 passes through the center of the slight detection hole 12 a.

Since the second hour intermediate wheel 12 and the hour wheel 14 of the first drive train 10 in the hour wheel system together constitute the first drive train 10, one rotation is directly related to the other rotation, but the rotational position of the detection hole 12a of the second hour intermediate wheel 12 and the rotational position of the detection hole 14a of the hour wheel 14 are assembled without being related to each other. Therefore, since the hour wheel system is at the reference position SK1, even if the detection hole 12a of the second hour intermediate wheel 12 is disposed at a position that can be detected by the first detection unit 50, the position of the detection hole 14a of the hour wheel 14 disposed at the second detection unit 60 is not specified.

Further, even if the light is not detected by rotating the second intermediate wheel 12 by 1 turn, since it is conceivable that the amount of light emitted from the LED chip 51 is low or the detection sensitivity of the phototransistor 52 is low, the control unit 70 performs an operation of searching the reference position SK1 by the light detection operation in addition to a control of increasing the amount of light emitted from the LED chip 51 or increasing the detection sensitivity of the phototransistor 52.

(2) Next, detection of the reference position SK2 of the second drive train 20 in the minute-second wheel system is carried out.

The detection holes in the minute-second wheel system were formed in 1 on the second wheel 24 (minute hand gear: 1 rotation every 1 hour), 1 on the fourth wheel 22 (second hand gear: 1 rotation every 1 minute), 2 on the third wheel 23 (gear mediating the second wheel 24 and the fourth wheel 22: 1 rotation every 1 hour) (angular interval 180[ degrees ]). The second wheel 24 and the fourth wheel 22 are arranged coaxially. The detection hole 24a of the second wheel 24 and the detection hole 22a of the fourth wheel 22 are arranged to overlap each other in the axial direction of the second drive train 201 time every 1 hour.

When the detection hole 24a of the second wheel 24 and the detection hole 22a of the fourth wheel 22 are axially overlapped, the detection hole 23a of the third wheel 23 is also formed to be overlapped with the detection hole 24a of the second wheel 24 and the detection hole 22a of the fourth wheel 22. Since the rotation period of the third wheel 23 is 8 minutes, the third wheel 23 rotates 7.5 revolutions while the second wheel 24 rotates 1 revolution, and 2 detection holes 23a are formed in the third wheel 23 at an angular interval of 180 degrees corresponding to 0.5 revolution in such a manner that the detection hole 24a of the second wheel 24, the detection hole 23a of the third wheel 23, and the detection hole 22a of the fourth wheel 22 are axially overlapped in a period of 1 hour and 1 time.

Since the second wheel 24 and the fourth wheel 22 rotate coaxially in the same direction, the opening formed in the plan view direction by overlapping the detection holes 24a, 22a in the axial direction with each other gradually increases and gradually decreases as the second wheel 24 and the fourth wheel 22 rotate, and the detection hole 24a of the second wheel 24 and the detection hole 22a of the fourth wheel 22 rotate. Therefore, even if the inspection hole 24a of the second wheel 24 and the inspection hole 22a of the fourth wheel 22 are both circular, only a part of 2 less inspection holes 22a, 24a are continuously overlapped with each other in a plurality of step ranges corresponding to the second stepping motor 41 of the minute-second wheel system.

The hour wheel 14 of the hour train wheel is arranged coaxially with the second wheel 24 and the fourth wheel 22, since the hour hand 4 (see fig. 1) is attached. The hour wheel 14 is also provided with a detection hole 14a axially overlapping the detection hole 24a of the second wheel 24, the detection hole 23a of the third wheel 23, and the detection hole 22a of the fourth wheel 22 at an interval of 1 hour and 1 time. Since the hour wheel 14 rotates 1 turn every 12 hours, 12 detection holes 14a may be formed at equal angular intervals of 30 degrees on the hour wheel 14, but 1 detection hole 14a of the 12 is intentionally omitted in order to detect the rotational position of the hour wheel 14. Therefore, 11 detection holes 14a are formed at equal angular intervals of 30 degrees on the hour wheel 14, and the angular interval between only 2 detection holes 14a, 14a at both ends among the 11 detection holes 14a arranged in the circumferential direction at equal angular intervals is 60 degrees.

Further, since the second wheel 24, the third wheel 23, and the fourth wheel 22 are the second drive train 20 in the minute-second wheel system and are driven by the second stepping motor 41 in the minute-second wheel system, the relative positional relationship is fixed, and the detection hole 24a of the second wheel 24, the detection hole 23a of the third wheel 23, and the detection hole 22a of the fourth wheel 22 are assembled so as to overlap in the axial direction at a ratio of 1 time (equivalent to 3600 steps for driving the second stepping motor 41) in a normal needle transport.

The hour wheel 14, on the other hand, is the first drive train 10 in an hour wheel system and rotates independently of the second drive train 20. Therefore, the relative positional relationship of the hour wheel 14 with respect to the second wheel 24, the third wheel 23, and the fourth wheel 22 is uncertain, and in a state where the detection hole 24a of the second wheel 24, the detection hole 23a of the third wheel 23, and the detection hole 22a of the fourth wheel 22 are axially overlapped, the detection hole 14a of the hour wheel 14 and the 3 detection holes 24a, 23a, and 22a overlapped with each other are not limited to being axially overlapped.

Fig. 6 is a plan view showing a state in which the detection hole 14a of the hour wheel 14, the detection hole 24a of the second wheel 24, the detection hole 23a of the third wheel 23, and a part of the detection hole 22a of the fourth wheel 22 overlap each other in the axial direction. As shown in fig. 6, an opening H through which light emitted from the LED chip 61 reaches the phototransistor 62 is formed in a state in which the detection hole 14a of the hour wheel 14, the detection hole 24a of the second wheel 24, the detection hole 23a of the third wheel 23, and the detection hole 22a of the fourth wheel 22 are axially overlapped. The larger the area of the opening H is, the wider the overlapping range of all the detection holes 14a, 24a, 23a, and 22a is, and the control unit 70 detects the position where the area of the opening H is the largest as the reference position SK2 of the minute-second wheel system.

(a) First, in the state where the hour wheel system is at the reference position SK1, the controller 70 detects the second stepping motor 41 in the minute-second wheel system by using the second detector 60 and drives 3600 steps at maximum. When the drive can be detected halfway through the 3600 steps, even if the drive is performed before the 3600 steps, the drive is terminated at a detectable time point. Not limited to the minute-second wheel system, the detection hole 24a of the second wheel 24, the detection hole 23a of the third wheel 23, and the detection hole 22a of the fourth wheel 22 must be overlapped in the axial direction 1 time during the 3600-step driving of the second stepping motor 41.

Here, since the relationship between the hour wheel 14 of the hour wheel system and the second drive train 20 of the minute-second wheel system is uncertain, the phototransistor 62 does not detect the light emitted from the LED chip 61 even if the second stepping motor 41 is driven 3600 steps unless the detection hole 14a of the hour wheel 14 is not stopped in a state where the detection hole 24a of the second wheel 24, the detection hole 23a of the third wheel 23, and the detection hole 22a of the fourth wheel 22 are overlapped in the axial direction.

Further, as described above, the detection hole 14a of the hour wheel 14 forms an angle of 15[ degrees ] or more in conversion to the angle around the rotation center C of the hour wheel 14, and a portion (shielding portion) having no opening between 2 detection holes 14a, 14a adjacent in the circumferential direction is the angle around the rotation center C of the hour wheel 14 and is smaller than 15[ degrees ].

(b) In the above (a), when the photo transistor 62 detects light, the process proceeds to the step (c) of improving the accuracy of the detection position, where the position of the first stepping motor 31 at the time of detection is set to the initial detection position SK11, and the position of the second stepping motor 41 is set to the initial detection position SK 21.

On the other hand, when the photo transistor 62 cannot detect light, (i) the hour wheel 14 is set to the advance state from 30 minutes (angle 15[ degree ]; 30 steps of the first stepping motor 31 from the reference position SK 1). Since the angle of the masking portion 14s around the rotation center C between the detection holes 14a, 14a of the hour wheel 14 is smaller than 15[ deg. ], the angle of deviation from the detection hole 14a of the hour wheel 14 is also smaller than 15[ deg. ] at the maximum, that is, smaller than 30[ deg. ] of the hour wheel 14, in the state where the detection hole 24a of the second wheel 24, the detection hole 23a of the third wheel 23, and the detection hole 22a of the fourth wheel 22 are axially overlapped. Therefore, by advancing or delaying the hour wheel 14 by 30[ minute ], the detection hole 14a of the hour wheel 14 is surely overlapped with the detection holes 24a of the second wheel 24, 23a of the third wheel 23, and 22a of the fourth wheel 22 in the axial direction.

(ii) Therefore, the control unit 70 controls the first stepping motor 31 so as to advance the hour wheel 14 by 30 minutes. Specifically, the first stepping motor 31 is rotated only in the forward direction for 30 steps. Accordingly, the first stepping motor 31 is in a state advanced by 30 steps with respect to the reference position SK 1.

In a state where the first stepping motor 31 is stopped, the controller 70 controls the second stepping motor 41 to drive 3600 steps again. Accordingly, during 3600 steps of rotation of the second drive train 20 in the minute-second wheel system, the detection hole 14a of the hour wheel 14, the detection hole 24a of the second wheel 24, the detection hole 23a of the third wheel 23, and the detection hole 22a of the fourth wheel 22 are overlapped in the axial direction, that is, a state in which the phototransistor 62 detects light emitted from the LED chip 61 is obtained. The process proceeds to step (c) in which the position of the first stepping motor 31 when the phototransistor 62 detects light is set to the initial detection position SK11, and the position of the second stepping motor 41 is set to the initial detection position SK21, thereby improving the detection position accuracy.

In general, detection can be performed by performing the above (a) and (b) 1 time. However, since the angle interval of the 2 detection holes 14a, 14a adjacent to each other in the circumferential direction is formed by a 60[ deg ] portion in the hour wheel 14, when the shielding portion as the 60[ deg ] interval is located at a position where the detection hole 24a of the second wheel 24, the detection hole 23a of the third wheel 23 and the detection hole 22a of the fourth wheel 22 overlap each other in the axial direction, the hour wheel 14 may be pushed 30[ deg ] to perform the operation (b) described above, and the light may not be detected. In this case, the light can be detected by repeating the above (a) and (b) 2 more times.

If the detection is not possible, the amount of light emitted from the LED chip 61 is low or the detection sensitivity of the phototransistor 62 is low, so that the control section 70 performs the detection of the light after performing control such as increasing the amount of light emitted from the LED chip 61 or increasing the detection sensitivity of the phototransistor 62.

(c) With the above-described (a), (b) (i), and (ii), the degree to which the detection holes 24a, 23a, and 22a of the second drive train 20 (second wheel 24, third wheel 23, and fourth wheel 22) overlap each other at the initial detection position SK11, SK12 at which the phototransistor 62 can initially detect light is unclear, or the degree to which the detection holes 24a, 23a, and 22a in these minute-second wheel systems overlap the detection hole 14a of the hour wheel 14 of the hour wheel system is unclear.

Therefore, the position where the area of the opening H formed by the overlapping of the 3 detection holes 24a, 23a, and 22a of the second drive train 20 and the detection hole 14a of the first drive train 10 is the largest is detected by the control of the following control unit 70. The position where the area of this opening H constitutes the maximum is determined as the reference position SK2 in the minute-second wheel system, and the phase difference (difference in the number of steps) between the reference position SK1 of the hour wheel system and the reference position SK2 of the minute-second wheel system is determined.

(i) First, the controller 70 rotates the second stepping motor 41 in the reverse direction (in the direction opposite to the normal needle-moving direction) for 6 steps from the initial detection position (hour wheel system: SK11, minute second wheel system: SK21) at which the light can be detected in the above-described initial minute-second wheel system. The position of the minute-second wheel system at this time is set as the search initial position SK 22. Here, since the first stepping motor 31 is not driven, the hour wheel 14 does not rotate. Since the fourth wheel 22 is also rotated in the reverse direction by 36[ degrees ] by the 6-step reverse rotation of the second stepping motor 41, the phototransistor 62 in the minute-second wheel system does not detect light at the initial search position SK22 (the initial detection position SK11 in the hour wheel system) in the minute-second wheel system. Further, the second wheel 24 is rotated only less than 1[ degree ] by the 6-step driving of the second stepping motor 41.

Since the number of steps of mounting the second stepping motor 41 on the search initial detection position SK22 to rotate in reverse is not limited to 6 steps, it is sufficient to return to a state where light cannot be reliably detected by the phototransistor 62, and therefore, it may be 7 steps or more or 5 steps or less as long as a state where light cannot be detected is reached.

However, since the above-described operation of rotating in the reverse direction to make the state in which light cannot be detected is performed, and then rotating in the forward and reverse directions again to search for a detectable state, even when the undetectable state is set to continue for a long period of time in a range of 7 steps or more, the time required to reach the detection state becomes long, and the time required to reach the detection state increases. Therefore, it is preferable to set the minimum number of steps in order to return to an exact undetected state.

In the case of 5 steps or less, there is a possibility that the state of being reliably undetectable is not obtained in 1 step and 2 steps. Therefore, the number of reverse rotation steps may be determined based on a previous experiment, design values, and the like, and in the present example, the number of reverse rotation steps is set to 6 steps based on such an experiment, design values, and the like.

(ii) In the above-described (i), the second stepping motor 41 that rotates in the reverse direction for 6 steps is stopped at the search initial position SK22, and then the control unit 70 rotates in the reverse direction for at least 60 steps for the first stepping motor 31. The number of steps of the reverse rotation is not limited to 60 steps, and may be 90 steps or 120 steps. The position of the time wheel system at this time is set as the search initial position SK 12. Accordingly, the hour wheel 14 rotates reversely for 1 hour, i.e., at an angle of 30[ deg. ] around the rotation center C of the hour wheel 14. The phototransistor 62 is kept in a state of not detecting light in the search initial position SK 12.

(iii) Next, the control unit 70 rotates the first stepping motor 31 forward 1 step by step from the search initial position SK12, and searches (searches) for a position where the phototransistor 62 can detect light. The position of the first stepping motor 31 which is rotated forward 1 step by step from the search initial position SK12 is set as the search position SK 13. The range of the forward rotation of the first stepping motor 31 is set to be more than 60 steps and less than 120 steps.

(iv) Next, the control unit 70 rotates the first stepping motor 31 in the forward direction in a range of more than 60 steps and less than 120 steps from the search initial position SK12, then returns the hour wheel system to the search initial position SK12 (performs reverse rotation), and rotates the second stepping motor 41 in the forward direction only by 1 step from the search initial position SK22, and then performs the operation of (iii) again. The position of the second stepping motor 41 that is rotated forward 1 step by step from the search initial position SK22 is set as the search position SK 23.

Fig. 7 is a plan view corresponding to fig. 6 showing an example of when the phototransistor 62 starts detecting light (detection start position) in the operation (c) and (iii), fig. 8 is a plan view corresponding to fig. 6 showing an example of before the phototransistor 62 finishes detecting light (position before the detection finishes), and fig. 9 is a plan view of fig. 6 showing an example of detecting an intermediate position. In the operation of (iii), the mode control unit 70 repeats the search operation of (iii) and the operation of (iv) (only rotating the second stepping motor 41 in the forward direction for 1 step) if the phototransistor 62 cannot detect light.

On the other hand, as shown in fig. 7, when the phototransistor 62 starts detecting light in the operation (iii), the position of the hour wheel system at which the light starts to be detected is set as the detection start position SK13 s. After the light is detected at the detection start position SK13s, the rotation of the hour wheel 14 is advanced, and as shown in fig. 8, the position of the hour wheel system at the previous rotational position (the rotational position corresponding to 1 step before the number of steps at which the light cannot be detected) at which the phototransistor 62 cannot detect the light is set as the position SK13e before the end of the detection.

The control unit 70 calculates a detection intermediate position SK14 (SK13s + SK13e)/2) which is an intermediate position between the detection start position SK13s and the position SK13e before the end of detection. Then, the control unit 70 reversely rotates the first stepping motor 31, and returns the hour wheel 14 to the detection neutral position SK14 as shown in fig. 9. The second detector 60 continuously detects light at a plurality of positions from the detection start position SK13s of the hour wheel system to the position SK13e before the end of detection, but the detection intermediate position SK14 is estimated to be the position where the most light is detected.

(v) In a state where the first stepping motor 31 is disposed at the detection intermediate position SK14, the control section 70 performs control for reducing the amount of emitted light of the LED chip 61 in stages. The control section 70 controls to reduce the amount of emitted light and to increase the light receiving sensitivity (an example of the detection level) of the phototransistor 62 in stages. By thus reducing the amount of light emitted from the LED chip 61, the phototransistor 62 cannot detect light even if the light receiving sensitivity of the phototransistor 62 becomes high. In the process of increasing the light reception sensitivity while reducing the amount of emitted light in this way, the control section 70 generates and stores in the storage section 71 a light reception sensitivity P before the phototransistor 62 cannot detect light in correspondence with the search position SK23 of the minute-second wheel system.

(vi) After the detection operation of the light reception sensitivity P at the detection intermediate position SK14 of the hour wheel system is completed, the control unit 70 returns the hour wheel system to the initial search position SK12, (iv), that is, performs the search operation of (iii) again after rotating the minute-second wheel system in the forward direction by only 1 step, and further performs the detection of the light reception sensitivity P corresponding to the search position SK23 of the minute-second wheel system in (v).

Fig. 10 is a graph in which the detected light reception sensitivity P of each search position SK23 detected by the operations (c) (v) and (vi) is plotted on the horizontal axis with the search position SK23 of the Hui minute-second round system and on the vertical axis with the light reception sensitivity P. As shown in fig. 10, any of the light reception sensitivities P detected at the respective search positions SK23 detected by the above-described actions (v) and (vi) corresponds to the search position SK23 and represents the maximum value. The maximum light reception sensitivity P indicates that the area of the opening H formed by overlapping the detection holes 14a, 24a, 23a, and 22a is the largest.

Therefore, the light reception sensitivity P constitutes the maximum value at the search position SK23 of the minute-second wheel system (SK 23 ═ a in fig. 10) and the detection intermediate position SK14 of the wheel system.

The control section 70 sets the search position SK23 thus detected as the reference position SK2 of the minute-second wheel system, and stores the light reception sensitivity P in the storage section 71 in association with the generation of SK 2. In addition, since the detected intermediate position SK14 of the hour wheel system at this time indicates the phase difference of the reference position SK2 of the minute-second wheel system corresponding to the reference position SK1 of the hour wheel system, the control unit 70 also stores the detected intermediate position SK14 of the hour wheel system in the storage unit 71.

The reference position SK1 of the hour wheel system, the reference position SK2 of the minute second wheel system, and the detected intermediate position SK14 indicating the phase difference between the reference position SK1 of the hour wheel system and the reference position SK2 of the minute second wheel system, which are stored in the storage unit 71 in this way, are set as reference positions in advance of the radio-controlled timepiece 1, and when detecting the hand positions thereafter, the stepping motors 31 and 41 or the detection units 50 and 60 are controlled by the control unit 70, respectively, in the same manner as the above-described operation, and the determination unit 72 can determine that there is no deviation from the reference positions.

In the present embodiment, the control unit 70 repeatedly executes the operations (v) and (vi) from the initial position SK22 to about 8 steps of forward rotation in the second stepping motor 41 of the minute-second wheel system, but the mode control unit 70 may stop the operations (v) and (vi) when the maximum value of the light reception sensitivity P is detected, that is, when the increased light reception sensitivity P changes to decrease. By stopping the operations (v) and (vi) in this way, the control unit 70 can shorten the time required to detect the reference position.

The needle position detection is performed by rotation in the forward rotation direction. In setting the reference position, if the train wheel rotates in the reverse direction, the train wheel (detection hole) may not move due to backlash. In such rotation in the reverse direction, although the control section 70 counts the number of steps by the command for driving the stepping motor, if the gear train does not move due to backlash, the reference position may be set erroneously. Therefore, in the case where the wheel train rotates in the reverse direction, it is preferable to perform additional reverse rotation beyond the rotation angle corresponding to the backlash of the wheel train having the detection hole and then rotate in the forward rotation direction.

(cross-reference to related applications)

The present invention claims priority based on the application of Japanese patent application 2015-206404 to the office at 10/20/2015 and application 2016-100294 to the office at 2016 at 5/19/2016, the disclosures of which are incorporated herein by reference in their entirety.

Claims (8)

1. An electronic timepiece is characterized in that,

the disclosed device is provided with:

a display unit that displays time by at least a first indication member and a second indication member;

a first drive train driving the first indicator member;

a second drive train driving the second indicator member;

the first drive train having a portion axially non-overlapping with the second drive train and a portion axially overlapping with the second drive train;

the non-overlapping portions have a first specific portion;

the overlapped portion has a second specific portion;

the second drive train has a third specific portion axially overlapping the second specific portion;

a first detector that detects the first specific portion;

a second detector that detects an overlap of the second specific portion and the third specific portion in the axial direction;

a control unit that controls driving of the first drive train and the second drive train based on a correspondence relationship, which is a reference of the first drive train and the second drive train, determined by a position of the first specific portion detected in advance by the first detector and a position of overlap in an axial direction of the second specific portion and the third specific portion detected in advance by the second detector,

the controller is provided with:

a storage unit that stores, as a correspondence relationship to the reference, the number of steps of driving the first drive train corresponding to a time difference between the first drive train and the second drive train until a reference position of the second drive train is detected after a reference position of the first drive train is detected; and

and a determination unit that determines whether or not the time indicated by the first and second indicator members is correct based on an actual correspondence relationship that is determined by a position of the first specific portion detected by the first detector and a position of overlap in the axial direction of the second specific portion and the third specific portion detected by the second detector, and the correspondence relationship that is stored in the storage unit as the reference.

2. Electronic timepiece according to claim 1,

the first specific portion is a detection hole of a single gear in the first drive train.

3. Electronic timepiece according to claim 2,

when the determination unit determines that the indication of the time is an error, the control unit drives the first drive train and the second drive train so that the actual correspondence relationship becomes the correspondence relationship as the reference.

4. Electronic timepiece according to claim 1,

when the first specific portion is continuously detected by the first detector at a plurality of positions at which the first drive train is driven, the control section sets, as the position detected by the first detector, a position at which a detection level becomes the largest among detection levels respectively detected at the plurality of positions detected by the first detector.

5. Electronic timepiece according to claim 2,

when the first specific portion is continuously detected by the first detector at a plurality of positions at which the first drive train is driven, the control section sets, as the position detected by the first detector, a position at which a detection level becomes the largest among detection levels respectively detected at the plurality of positions detected by the first detector.

6. An electronic timepiece according to claim 3,

when the first specific portion is continuously detected by the first detector at a plurality of positions at which the first drive train is driven, the control section sets, as the position detected by the first detector, a position at which a detection level becomes the largest among detection levels respectively detected at the plurality of positions detected by the first detector.

7. The electronic timepiece according to any one of claims 1 to 4,

when the overlap in the axial direction of the second specific portion and the third specific portion is continuously detected by the second detector at a plurality of positions where the first drive train is driven and at a plurality of positions where the second drive train is driven, the control section sets, as the position detected by the second detector, a position at which a detection level becomes the largest among detection levels respectively detected at the plurality of positions detected by the second detector.

8. The electronic timepiece according to any one of claims 1 to 4,

when the overlap in the axial direction of the second specific portion and the third specific portion is continuously detected by the second detector at a plurality of positions where the first drive train is driven and at a plurality of positions where the second drive train is driven, the control portion sets, as the position detected by the second detector, a position at which a detection level becomes the largest among detection levels detected at intermediate positions of the plurality of positions of the first drive train corresponding to the plurality of positions of the second drive train detected by the second detector, respectively.

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